Hundreds of demonstrations are taking place throughout the day across the country on Friday.
National Nurses United (NNU), comprising of over 150,000 registered nurses, is holding about 140 rallies in 13 states in order to urge authorities to provide them masks and other protective equipment.
"When nurses are not protected, patients are not protected too,", NNU Executive Director Bonnie Castillo said on Twitter.
However, Castillo added, nurses signed up to treat people, but not to sacrifice themselves on the front line of the coronavirus battle.
"On this day that celebrates the labor movement and working people, union nurses are standing up to demand the protections they need now!" she said.
Dozens of nurses and those sympathetic to them gathered outside hospitals in the city of Oakland, California.
"Protect nurses and patients!" they chanted, according to videos released on NNU's Twitter account.
They also urged local officials to respect medical workers.
Another 50 nurses have participated in silent prayer outside Keck Medical Center at the University of Southern California in Los Angeles. They signed a petition and rigged up a heart using rose candles.
"We need N95 Masks to Survive", many posters said.
Similar actions took place inside and outside of hospitals in other major cities, including Washington, New York, and Chicago.
Meanwhile, thousands of people gathered in nationwide protests against stay-at-home orders issued by authorities to combat the coronavirus spread.
"All Jobs Essential," chanted people gathered in the city of Dover, Delaware. They urged to "End Tyranny" meaning mandatory order to continue stay out of work and schools.
In Chicago, many activists have participated in "Re-Open Illinois" rally. People, some of whom were armed, expressed their opposition to Governor JB Pritzker to extend the stay-at-home order, NBC News said.
"We feel like our rights have been taken away without a plan", one protester told local radio.
Many rallies across the nation took place under the slogan "Make America Great Again May Day".
"It is time to take a stand for liberty", organisers said in statement. They accused authorities of attempts to "infringe upon many basic rights of citizens."
"We want to have liberty to make the decision to engage in activities we, as free people, desire", they said.
US economy has been shuttered by the coronavirus pandemic. Manufacturing sector activity hit an 11-year low in April as the outbreak kept most American businesses shuttered for a second month in a row, while energy markets weakened as well, data and analysis from the Institute for Supply Management (ISM) revealed.